The arrangement of atoms and molecular groups in DNA and RNA can be studied using

Options

A. Centrifugation
B. Spectrophotometer
C. X- ray diffraction
D. Histochemistry

Answer

To answer the question regarding the arrangement of atoms and molecular groups in DNA and RNA, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks about the methods used to study the arrangement of atoms and molecular groups in DNA and RNA.

2. **Identifying Relevant Techniques**: In molecular biology, several techniques are used to analyze the structure of biomolecules. The most relevant techniques include X-ray diffraction, nuclear magnetic resonance (NMR), and other structural biology methods.

3. **Focusing on X-ray Diffraction**: Among the techniques mentioned, X-ray diffraction is particularly significant. This method allows scientists to obtain highly detailed images of the molecular structure of DNA and RNA. It works by directing X-rays at a crystal of the molecule, which then diffracts the X-rays in a pattern that can be analyzed.

4. **Understanding the Mechanism**: X-ray diffraction produces a three-dimensional image of the molecules, similar to how our eyes perceive images through light. This method reveals the arrangement of atoms and provides insight into the molecular forces and structures that underpin biological functions.

5. **Evaluating Other Options**:
- **Centrifugation**: This technique separates molecules based on density but does not provide structural information.
- **Spectrophotometry**: This method measures the absorbance of light by molecules but does not reveal atomic arrangements.
- **Histochemistry**: This focuses on the distribution of chemical constituents in tissues using staining techniques, which is not directly related to studying molecular structures.

6. **Conclusion**: Based on the analysis, the correct answer to the question is **X-ray diffraction**.

### Final Answer:
The arrangement of atoms and molecular groups in DNA and RNA can be studied using **X-ray diffraction**.

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